Journal
INTERNATIONAL JOURNAL OF CANCER
Volume 111, Issue 6, Pages 849-857Publisher
WILEY
DOI: 10.1002/ijc.20334
Keywords
antisense; siRNA; apoptosis; HIF-1 alpha; Bcl-2; IAP-2
Categories
Funding
- NCRR NIH HHS [P20-RR16463] Funding Source: Medline
- NIAMS NIH HHS [1S11 AR47359] Funding Source: Medline
Ask authors/readers for more resources
Overexpression of hypoxia inducible factor-1alpha (HIF-1alpha) in cancers has been correlated to a more aggressive tumor phenotype. We investigated the effect of HIF-1alpha knockout on the in vitro survival and death of human tongue squamous cell carcinomas (SCC-4 and SCC-9). Under normoxic condition, a basal level of HIF-1alpha protein was constitutively expressed in SCC-9 cells, albeit an undetectable level of HIF-1alpha messages. Exposure to hypoxia induced only a transient increase in mRNA transcript but a prolonged elevation of HIF-1alpha protein and its immediate downstream target gene product, VEGF. Under normoxic or hypoxic conditions, treatment of SCC-9 cells with AS-HIF-1alpha ODN suppressed both constitutive and hypoxia-induced HIF-1alpha expression at both mRNA and protein levels Knockout of HIF-1alpha gene expression via either AS-HIF-1alpha ODN or siRNA (siRNA(HIF-1alpha)) treatment resulted in inhibition of cell proliferation and induced apoptosis in SCC-4 and SCC-9 cells. We also demonstrated that exposure of SCC-9 cells to hypoxia led to a time-dependent increase in the expression of bcl-2 and IAP-2, but not p53. The attenuated levels of bcl-2 and IAP-2, and the enhanced activity of caspase-3 after treatment with AS-HIF-1alpha ODN may contribute partly to the effects of HIF-1alpha blockade on SCC-9 cell death. Collectively, our data suggest that a constitutive or hypoxia-induced expression of HIF-1alpha in SCC-9 and SCC-4 cells is sufficient to confer target genes expression essential for tumor proliferation and survival. As a result, interfering with HIF-1alpha pathways by antisense or siRNA strategy may provide a therapeutic target for human tongue squamous cell carcinomas. (C) 2004 Wiley-Liss, Inc.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available